A display apparatus in related art is supplied with electric energy by an external power supply apparatus. For example, a television is supplied with an electric signal mainly by an external power supply. For another example, although a mobile phone itself includes a battery used for storing electric energy, the battery must be charged by an external power supply before being used; and when the battery is exhausted, it has to be charged by the external power supply for further use.
As can be seen, the related display apparatus has to rely on an external power supply apparatus to implement display, especially for mobile display apparatuses such as the mobile phone, which results in problems of inconvenience in use and the like.